Objects and Meshes not showing up on collections tab
i think you have added your mesh to the mesh &quot;Cube.001&quot; via SHIFT+A in Edit Mode. If you want to make a separate object instead of adding this into an other mesh, go in Object Mode and hit SHIFT+A.
But you can also separate parts of meshes or merge them anytime.
F.e - if you want to separate the door from the rest of the house, select a part of your door mesh, hit CTRL+L to select linked vertices and then hit P and select &quot;Separate Selection&quot;.
But if you want to merge your door with the house again, select both of your objects and press CTRL+J. Let me know if it was helpful.